Graph

Graph/c_DirectedCycle.h

@@ -0,0 +1,55 @@
+#ifndef INCLUDED_C_DIRECTEDCYCLE_H
+#define INCLUDED_C_DIRECTEDCYCLE_H
+
+#ifndef INCLUDED_C_DIGRAPH_H
+#include <c_Digraph.h>
+#endif /*INCLUDED_C_DIGRAPH_H*/
+
+#ifndef INCLUDED_C_VERTEXIDLIST_H
+#include <c_VertexIdList.h>
+#endif /*INCLUDED_C_VERTEXIDLIST_H*/
+
+
+
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+typedef struct {
+    c_bool_t*      marked;      /* Visited tracking array (size of graph->V) */
+    c_size_t*      edge_to;     /* edge_to[w] = last edge on path to w */
+    c_bool_t*      on_stack;    /* Keeps track of vertices currently on the recursive DFS stack */
+    c_VertexIdList_t    cycle;       /* Stores the cycle sequence if found */
+    c_Allocator_t  allocator;   /* Deep copy of the user-provided allocator */
+} c_DirectedCycle_t;
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+/**
+ * @brief Determines if the digraph has a directed cycle, and if so, finds one.
+ * @param allocator Explicit allocator context used to allocate internal routing arrays
+ */
+c_err_t c_DirectedCycle_Init(c_DirectedCycle_t* self, const c_Digraph_t* graph, c_Allocator_t* allocator);
+
+/**
+ * @brief Releases internal tracking buffers
+ */
+void c_DirectedCycle_Destroy(c_DirectedCycle_t* self);
+
+/**
+ * @brief Does the digraph have a directed cycle?
+ */
+C_STATIC_FORCE_INLINE c_bool_t c_DirectedCycle_HasCycle(c_DirectedCycle_t* self) {
+    if (!self) return C_FALSE;
+    return !c_VertexIdList_IsEmpty(&self->cycle);
+}
+
+/**
+ * @brief Gets the vertices on a directed cycle.
+ * @param out_cycle An initialized c_VertexIdList_t container to collect the sequence.
+ */
+c_err_t c_DirectedCycle_GetCycle(c_DirectedCycle_t* self, c_VertexIdList_t* out_cycle);
+
+
+#endif /*INCLUDED_C_DIRECTEDCYCLE_H*/